A mass shooting at two mosques in Christchurch, New Zealand, have left at least 49 worshippers dead. At least 20 other people have been seriously injured. Prime Minister Jacinda Ardern is calling it New Zealand's darkest day.

LIANNE DALZIEL: You know, the 15 of March is just going to be one of those days that will live on forever in our memories as a city.

MARTIN: Patrick Gower is a national correspondent for the Newshub news network in New Zealand. He is on the line now from Christchurch. Patrick, thanks so much for being with us this morning.

PATRICK GOWER: No problem. No problem.

MARTIN: Can you explain, as best you know, the mechanics of the attack? What do we know about what happened?

GOWER: Yeah. So Friday, obviously a day of worship at these mosques - two mosques here in Christchurch. And while they were both full with followers praying, a gunman went in, streaming on the Internet, and began shooting them in the back as they tried to escape and could not get through a door at the back of the mosque. And you've got to realize it's hundreds of people in this. He continued to shoot them. He shot them as they were chased out of the mosque and trying to jump across the fence into the back gardens of other homes in the neighborhood. At the same time, there was a simultaneous attack at another mosque nearby, where a similar event kind of happened with another gunman.

And I think what is the most important for your listeners to understand is that New Zealand does not have mass shootings. This is something that does not happen here. In fact, it's been 18 years since we had a mass shooting - in this country - of just 13 people. We do not have tension with Islamic people. We do not have tension with Muslims. There is nothing there. So this has come - in a very New Zealand saying - we say, this has come out of the blue.

MARTIN: Yeah.

GOWER: So it has left the country so shocked that this is happening.

MARTIN: One of the alleged gunman has been charged with murder. Can you tell us anything about the other people in custody?

GOWER: No, we know very little. The one that has been charged we know is an Australian. So he has come from across the Tasman Sea. We know that about him. We know quite a bit about him because he written a 37-page manifesto on the Internet, as well as the - as well as the livestreaming of the attack. So we know some of his motivations....

MARTIN: And...

GOWER: ...(Unintelligible) or shown by himself.

MARTIN: Does the - obviously, extremist views in this manifesto. Anything else that will - investigators will be following?

GOWER: Yeah, I mean, for investigators - you know, to be - to be brutally honest, it's been livestreamed. That's the sad reality of this is, actually, you - investigators can go and watch what happened. And I think New Zealanders will just not be able to compute this, really. We actually watch what happens with mass shootings in the United States with a certain kind of, it'll never happen here. And for something like this to happen - someone shooting Muslims, recording it, streaming it live on the Internet - is just something that just no New Zealander would ever have thought would have come here. And it's going to take us a long time to figure out how this happened.

MARTIN: Patrick, have you read this man's manifesto?

GOWER: Yeah. Yeah, I read it briefly on my way to Christchurch today. I live in the capital city, Wellington. So when this first started breaking out, I flew here straight away. And on the way down - as, you know, modern technology has - it's very easy to have the - have access to the manifesto. It was tweeted and whatnot.

MARTIN: What does it say specifically about motive?

GOWER: Yeah. It's - well, it's very confusing. He seems to have got a grudge with a mosque in another city in New Zealand where he was living, Dunedin, which is further south from here - in the very south of New Zealand. He seems to have got a grudge with them. The manifesto is long and rambling and, to be honest, does not connect with, you know, any - even the extremists that we do have in this country - there are very, very small number of white extremists or something like that. But the stuff that it - this man is writing about does not even connect with them. It's very, very random. It's not sort of connected to anything that we have. And I know I'm struggling to explain it to you, but it's come out of nowhere.

MARTIN: Yeah.

GOWER: It's not connected to anything. There's no movement that it's connected to. There's no buildup of tension.

MARTIN: Which is...

GOWER: It's nothing. It's just...

MARTIN: It's why people have been caught so off-guard. We will continue to follow this. We appreciate you sharing what you've learned. Patrick Gower, national correspondent for the Newshub network in New Zealand. Thank you.